Rafael Nadal was upset by big-hitting qualifier Martin Klizan of Slovakia 6-7 (7), 6-4, 6-3 in the quarterfinals of the China Open on Friday.
The second-seeded Spaniard struggled with Klizan's power game and his own consistency in just his third match back following a two-month layoff due to a right wrist injury.
Novak Djokovic and Andy Murray, meanwhile, set up a semifinal showdown with convincing wins over two young players enjoying breakthrough seasons.
The top-seeded Djokovic defeated Wimbledon semifinalist Grigor Dimitrov of Bulgaria 6-2, 6-4, while sixth-seeded Murray took out U.S. Open champion Marin Cilic 6-1, 6-4.
On the women's side, Serena Williams withdrew before her quarterfinal against Samantha Stosur with a left knee injury that raised doubts about her ability to play the WTA Finals in Singapore this month.